Plant cell wall cross-linking is an important mechanism for regulating plant extension and providing a solid, dimensionally stable, polymer network. Ferulate, in arabinoxylan-ferulate esters, will dimerize via radical coupling mechanisms to cross-link wall polysaccharides. Ferulate and diferulates will also actively incorporate into lignins via radical processes, effecting polysaccharide-lignin cross-linking. Determining the sites of lignin attachment helps delineate diverse mechanisms and establishes the biochemistry of attachment. Recent NMR spectra provide compelling evidence for the role of ferulates as nucleation sites or initiation sites for lignification. However, detectability (and obtaining diagnostic correlational data) are difficult for these important but minor components of the plant cell wall.